Hyaluronan (HA) is a naturally-occurring unbranched polysaccharide that interacts with extracellular matrix proteins and with cell surface receptors; the latter interactions mediate inflammatory and metastatic downstream events. Echelon Research Laboratories proposes to develop new fluorescently-labeled reagents for detection of HA and of HA binding proteins (HABPs). The proposed HA-based product line would include (i) sized and calibrated standards of HA and HA-derived oligosaccharides, (ii) fluorescent probes for cell biology, immunocytochemistry, and biochemistry based on these standards, and (iii) a fluorescently-labeled recombinant HA binding domain for HA detection. In this Phase I feasibility study, we propose four specific aims: (i) generate and standardize HA fragments of different sizes; (ii) prepare and purify fluorescent HAs with three nonoverlapping fluorophores, (iii) develop fluorescence-based assays for HA-HABP interactions and hyaluronidase (HAse) activity, and (iv) develop a fluorescently-labeled recombinant HABP for HA detection in tissue samples, in cells, and on HA-coated biomaterial surfaces. PROPOSED COMMERCIAL APPLICATIONS: Reagents for specific detection of HA and HABPs would provide important.research and diagnostic tools for measurement of HAse activity and HA binding affinity. F1uorescence-based assays would permit high- throughput screening for HAse inhibitors or for antagonists of HA-HA receptor interactions. The reagents proposed could be used for the discovery of therapeutic anti-angiogenic, anti-metastatic, anti- inflammatory or anti-fertility compounds.